Poll devices at 1ms using Multimedia Timer

C#/AutoHotInterception/AutoHotInterception.csproj

@@ -42,6 +42,7 @@
   <ItemGroup>
     <Compile Include="Helpers\HelperFunctions.cs" />
     <Compile Include="Helpers\ManagedWrapper.cs" />
+    <Compile Include="Helpers\MultimediaTimer.cs" />
     <Compile Include="Manager.cs" />
     <Compile Include="Monitor.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

C#/AutoHotInterception/Helpers/MultimediaTimer.cs

@@ -0,0 +1,208 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace AutoHotInterception.Helpers
+{
+    public class MultimediaTimer : IDisposable
+    {
+        private const int EventTypeSingle = 0;
+        private const int EventTypePeriodic = 1;
+
+        private static readonly Task TaskDone = Task.FromResult<object>(null);
+
+        private bool disposed = false;
+        private int interval, resolution;
+        private volatile uint timerId;
+
+        // Hold the timer callback to prevent garbage collection.
+        private readonly MultimediaTimerCallback Callback;
+
+        public MultimediaTimer()
+        {
+            Callback = new MultimediaTimerCallback(TimerCallbackMethod);
+            Resolution = 5;
+            Interval = 10;
+        }
+
+        ~MultimediaTimer()
+        {
+            Dispose(false);
+        }
+
+        /// <summary>
+        /// The period of the timer in milliseconds.
+        /// </summary>
+        public int Interval
+        {
+            get
+            {
+                return interval;
+            }
+            set
+            {
+                CheckDisposed();
+
+                if (value < 0)
+                    throw new ArgumentOutOfRangeException("value");
+
+                interval = value;
+                if (Resolution > Interval)
+                    Resolution = value;
+            }
+        }
+
+        /// <summary>
+        /// The resolution of the timer in milliseconds. The minimum resolution is 0, meaning highest possible resolution.
+        /// </summary>
+        public int Resolution
+        {
+            get
+            {
+                return resolution;
+            }
+            set
+            {
+                CheckDisposed();
+
+                if (value < 0)
+                    throw new ArgumentOutOfRangeException("value");
+
+                resolution = value;
+            }
+        }
+
+        /// <summary>
+        /// Gets whether the timer has been started yet.
+        /// </summary>
+        public bool IsRunning
+        {
+            get { return timerId != 0; }
+        }
+
+        public static Task Delay(int millisecondsDelay, CancellationToken token = default(CancellationToken))
+        {
+            if (millisecondsDelay < 0)
+            {
+                throw new ArgumentOutOfRangeException("millisecondsDelay", millisecondsDelay, "The value cannot be less than 0.");
+            }
+
+            if (millisecondsDelay == 0)
+            {
+                return TaskDone;
+            }
+
+            token.ThrowIfCancellationRequested();
+
+            // allocate an object to hold the callback in the async state.
+            object[] state = new object[1];
+            var completionSource = new TaskCompletionSource<object>(state);
+            MultimediaTimerCallback callback = (uint id, uint msg, ref uint uCtx, uint rsv1, uint rsv2) =>
+            {
+                // Note we don't need to kill the timer for one-off events.
+                completionSource.TrySetResult(null);
+            };
+
+            state[0] = callback;
+            UInt32 userCtx = 0;
+            var timerId = NativeMethods.TimeSetEvent((uint)millisecondsDelay, (uint)0, callback, ref userCtx, EventTypeSingle);
+            if (timerId == 0)
+            {
+                int error = Marshal.GetLastWin32Error();
+                throw new Win32Exception(error);
+            }
+
+            return completionSource.Task;
+        }
+
+        public void Start()
+        {
+            CheckDisposed();
+
+            if (IsRunning)
+                throw new InvalidOperationException("Timer is already running");
+
+            // Event type = 0, one off event
+            // Event type = 1, periodic event
+            UInt32 userCtx = 0;
+            timerId = NativeMethods.TimeSetEvent((uint)Interval, (uint)Resolution, Callback, ref userCtx, EventTypePeriodic);
+            if (timerId == 0)
+            {
+                int error = Marshal.GetLastWin32Error();
+                throw new Win32Exception(error);
+            }
+        }
+
+        public void Stop()
+        {
+            CheckDisposed();
+
+            if (!IsRunning)
+                throw new InvalidOperationException("Timer has not been started");
+
+            StopInternal();
+        }
+
+        private void StopInternal()
+        {
+            NativeMethods.TimeKillEvent(timerId);
+            timerId = 0;
+        }
+
+        public event EventHandler Elapsed;
+
+        public void Dispose()
+        {
+            Dispose(true);
+        }
+
+        private void TimerCallbackMethod(uint id, uint msg, ref uint userCtx, uint rsv1, uint rsv2)
+        {
+            var handler = Elapsed;
+            if (handler != null)
+            {
+                handler(this, EventArgs.Empty);
+            }
+        }
+
+        private void CheckDisposed()
+        {
+            if (disposed)
+                throw new ObjectDisposedException("MultimediaTimer");
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (disposed)
+                return;
+
+            disposed = true;
+            if (IsRunning)
+            {
+                StopInternal();
+            }
+
+            if (disposing)
+            {
+                Elapsed = null;
+                GC.SuppressFinalize(this);
+            }
+        }
+    }
+
+    internal delegate void MultimediaTimerCallback(UInt32 id, UInt32 msg, ref UInt32 userCtx, UInt32 rsv1, UInt32 rsv2);
+
+    internal static class NativeMethods
+    {
+        [DllImport("winmm.dll", SetLastError = true, EntryPoint = "timeSetEvent")]
+        internal static extern UInt32 TimeSetEvent(UInt32 msDelay, UInt32 msResolution, MultimediaTimerCallback callback, ref UInt32 userCtx, UInt32 eventType);
+
+        [DllImport("winmm.dll", SetLastError = true, EntryPoint = "timeKillEvent")]
+        internal static extern void TimeKillEvent(UInt32 uTimerId);
+    }
+}

C#/AutoHotInterception/Manager.cs

@@ -34,7 +34,8 @@ namespace AutoHotInterception
         private readonly ConcurrentDictionary<int, ConcurrentDictionary<ushort, WorkerThread>> _workerThreads =
             new ConcurrentDictionary<int, ConcurrentDictionary<ushort, WorkerThread>>();
 
-        private Thread _pollThread;
+        private readonly MultimediaTimer _timer;
+        private readonly int _pollRate = 1;
         private volatile bool _pollThreadRunning;
 
         #region Public
@@ -44,6 +45,8 @@ namespace AutoHotInterception
         public Manager()
         {
             _deviceContext = ManagedWrapper.CreateContext();
+            _timer = new MultimediaTimer() { Interval = _pollRate };
+            _timer.Elapsed += DoPoll;
         }
 
         public void Dispose()
@@ -433,18 +436,19 @@ namespace AutoHotInterception
 
         private void SetThreadState(bool state)
         {
-            if (state)
+            if (state && !_timer.IsRunning)
             {
-                if (_pollThreadRunning) return;
-                _pollThreadRunning = true;
-                _pollThread = new Thread(PollThread);
-                _pollThread.Start();
+                SetFilterState(true);
+                _timer.Start();
             }
-            else
+            else if (!state && _timer.IsRunning)
             {
-                _pollThreadRunning = false;
-                _pollThread.Join();
-                _pollThread = null;
+                SetFilterState(false);
+                _timer.Stop();
+                while (_pollThreadRunning) // Are we mid-poll?
+                {
+                    Thread.Sleep(10); // Wait until poll ends
+                }
             }
         }
 
@@ -486,12 +490,11 @@ namespace AutoHotInterception
         }
 
         // ScanCode notes: https://www.win.tue.nl/~aeb/linux/kbd/scancodes-1.html
-        private void PollThread()
+        private void DoPoll(object sender, EventArgs e)
         {
+            _pollThreadRunning = true;
             var stroke = new ManagedWrapper.Stroke();
 
-            while (_pollThreadRunning)
-            {
             // Iterate through all Keyboards
             for (var i = 1; i < 11; i++)
             {
@@ -712,9 +715,7 @@ namespace AutoHotInterception
                 }
             }
 
-                // ToDo: Can this sleep be removed? Will removing it consume a lot of CPU? It will certainly make updates only happen once every ~10ms, which is too slow for mice polling @ 1khz
-                Thread.Sleep(10);
-            }
+            _pollThreadRunning = false;
         }
 
         private class MappingOptions

C#/AutoHotInterception/Monitor.cs

@@ -14,7 +14,8 @@ namespace AutoHotInterception
         private dynamic _keyboardCallback;
         private dynamic _mouseCallback;
 
-        private Thread _pollThread;
+        private readonly MultimediaTimer _timer;
+        private readonly int _pollRate = 1;
         private volatile bool _pollThreadRunning;
 
         #region Public
@@ -22,6 +23,8 @@ namespace AutoHotInterception
         public Monitor()
         {
             _deviceContext = ManagedWrapper.CreateContext();
+            _timer = new MultimediaTimer() { Interval = _pollRate };
+            _timer.Elapsed += DoPoll;
             SetThreadState(true);
         }
 
@@ -95,18 +98,19 @@ namespace AutoHotInterception
 
         private void SetThreadState(bool state)
         {
-            if (state)
+            if (state && !_timer.IsRunning)
             {
-                if (_pollThreadRunning) return;
-                _pollThreadRunning = true;
-                _pollThread = new Thread(PollThread);
-                _pollThread.Start();
+                SetFilterState(true);
+                _timer.Start();
             }
-            else
+            else if (!state && _timer.IsRunning)
             {
-                _pollThreadRunning = true;
-                _pollThread.Join();
-                _pollThread = null;
+                SetFilterState(false);
+                _timer.Stop();
+                while (_pollThreadRunning) // Are we mid-poll?
+                {
+                    Thread.Sleep(10); // Wait until poll ends
+                }
             }
         }
 
@@ -121,12 +125,12 @@ namespace AutoHotInterception
                 state ? ManagedWrapper.Filter.All : ManagedWrapper.Filter.None);
         }
 
-        private void PollThread()
+        private void DoPoll(object sender, EventArgs e)
         {
+            _pollThreadRunning = true;
+
             var stroke = new ManagedWrapper.Stroke();
 
-            while (_pollThreadRunning)
-            {
             for (var i = 1; i < 11; i++)
             {
                 while (ManagedWrapper.Receive(_deviceContext, i, ref stroke, 1) > 0)
@@ -200,8 +204,8 @@ namespace AutoHotInterception
                 }
             }
 
-                Thread.Sleep(10);
-            }
+
+            _pollThreadRunning = false;
         }
 
         private void FireKeyboardCallback(int id, KeyboardCallback data)

C#/TestApp/MonitorTester.cs

@@ -16,14 +16,16 @@ namespace TestApp
                 {
                     Console.WriteLine($"Keyboard: ID={id}, Code={code}, Value={value}, Info={info}");
                 }),
-                new Action<int, int, int, string>((id, code, value, info) =>
+                new Action<int, int, int, int, int, string>((id, code, value, x, y, info) =>
                 {
-                    Console.WriteLine($"Mouse: ID={id}, Code={code}, Value={value}, Info={info}");
+                    Console.WriteLine($"Mouse: ID={id}, Code={code}, Value={value}, X={x}, Y={y}, Info={info}");
                 })
             );
-            var devId = mon.GetKeyboardId(0x04F2, 0x0112);
-            mon.SetDeviceFilterState(devId, true);
+            var keyboardId = mon.GetKeyboardId(0x04F2, 0x0112);
+            mon.SetDeviceFilterState(keyboardId, true);
 
+            var mouseId = mon.GetMouseIdFromHandle(@"HID\VID_046D&PID_C00C&REV_0620");
+            mon.SetDeviceFilterState(mouseId, true);
         }
     }
 }